1. Field Of The Invention
Various different forms of semi-trailers are presently being manufactured including center sections which may be raised and lowered and which are referred to as "drop center" trailers.
A "drop center" trailer, in some instances, includes front and rear sections which are horizontally aligned and interconnected by a center section which may be raised and lowered between lower and upper positions thereof interconnecting the front and rear sections.
When the center section is horizontally aligned with the front and rear sections the trailer is termed a "flat" and may be used to transport various forms of bulk equipment and supplies. However, when the center section of the trailer is lowered to the low position thereof heavy loads may be carried by the trailer and be supported from the center section thereof, including those loads which may not be readily lifted to the high level of the front and rear sections of the trailer.
However, "single drop" trailers comprise trailers including a raised front section and somewhat lower and horizontally aligned rear and center sections. "Single drop" trailers are desired in many instances in that they may transport various different types of loads efficiently.
The trailer of the instant invention comprises a "single drop" trailer, but also includes a vertically adjustable center section and the front and rear sections of the single drop trailer of the instant invention are interconnected by the center section in a manner such that the trailer, when the three sections thereof are secured together, is stronger and also in a manner enabling changing of the center section between it's upper and lower positions in a minimum amount of time. In addition, the trailer is constructed in a manner whereby the trailer may be more quickly loaded with heavy loads.
2. Description Of Related Art
Various different forms of trailers including some of the general structural and operational features of the instant invention heretofore have been known. Examples of these different forms of trailers are disclosed in my prior U.S. Pat. No. 4,290,642 and also in U.S. Pat. Nos. 2,776,146, 2,970,861, 3,019,763 and 3,430,791. However, the "single drop" trailer of the instant invention includes combination of structural features which provide for an extremely strong trailer contruction and a trailer which may have its center section adjusted between its upper and lower positions in a minimum of time.